COBHAM ERU50-001 Operating instructions

Brand: COBHAM

Model: ERU50-001

Type: Operating instructions

Installation and Operation Manual

ERU50-001

Emergency Relay Unit

SM83-ERU50-804-0

ISSUE 1.01

IMPORTANT NOTICE

Chelton Avionics Inc. doing business as Wulfsberg Electronics

Division is responsible for full distribution and revisions of

ICA's (Instructions for Continued Airworthiness).

For inquiries regarding the content and currency of this

manual contact Wulfsberg Electronics Division, 6400

Wilkinson Drive, Prescott, Arizona, 86301. Telephone (928)

756-1615 or refer to the following website:

www.wulfsberg.com for more information.

SEALED

2012.11

.19 

17:46:3

2 -08'00'

ERU50-001 Emergency Relay Unit

SM83 Installation and Operation Manual

Installation and Operation Manual Issue 1.01 Page ii

CONFIDENTIAL AND PROPRIETARY TO COBHAM

Prepared By: Checked By: Approved By:

The status of this installation and operation manual is controlled by issue shown on the title page. The

status of each section is controlled by revision shown in the footer of each page. All revisions affecting

sections of this manual have been incorporated into the latest issue.

ISSUE/REVISION RECORD

Manual Issue

Number

Section

Revision Number

Revision Description Issue Date

1.01 All DCA W12809 Nov 15, 2012

1.00 Section 1 Rev: 1.00

Section 2 Rev: 1.00

Section 3 Rev: 1.00

Initial release Oct 22, 2009

Geoff Melton

2012.11.14 

18:30:02 -08'00'

Barb Page

2012.11.1

6 

09:25:46 

-08'00'

Zack 

Pahlman

2012.11.

19 

15:12:12 

-08'00'

ERU50-001 Emergency Relay Unit

SM83 Installation and Operation Manual

Installation and Operation Manual Issue 1.01 Page iii

CONFIDENTIAL AND PROPRIETARY TO COBHAM

Table of Contents

Section Title Page

1. Description

1.1 Introduction 1-1

1.2 Product Description 1-1

1.3 Design Features 1-1

1.4 Specifications 1-1

1.4.1 Electrical Specifications 1-1

1.4.2 Physical Specifications 1-3

1.4.3 Environmental Specifications 1-3

2. Installation

2.1 Introduction 2-1

2.2 Unpacking and Inspection 2-1

2.2.1 Warranty 2-1

2.3 Airworthiness Limitations 2-1

2.4 Installation Procedures 2-1

2.4.1 Warnings 2-2

2.4.2 Cautions 2-2

2.4.3 Cabling and Wiring 2-2

2.4.4 Post-Installation Checks 2-2

2.4.5 Functional Requirements 2-3

2.4.6 Minimum Performance Requirements 2-4

2.4.7 Alert Configuration 2-5

2.5 Accessories Required But Not Supplied 2-5

2.6 Installation Drawings 2-5

3. Operation

3.1 Introduction 3-1

3.2 General Information 3-1

ERU50-001 Emergency Relay Unit

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Section 1 Description

1.1 Introduction

Information in this section consists of product description, design features and specifications for the

ERU50-001 Emergency Relay Unit. All derivative product information shall be contained in the applicable

manual supplement, which may be obtained from Cobham as required.

Review all notes, warnings and cautions.

1.2 Product Description

The ERU50 is an Emergency Relay Unit for use with the Cobham Digital Audio Communication System

(DACS).

1.3 Design Features

The DACS is a management system that distributes and controls all of the transceiver, receiver and

warning source audio in an aircraft. It enables the transmission of microphone audio to a selected

Transceiver and distributes all Inter-Communication System (ICS) audio.

The ERU50 allows continued communications between a crew member and cabin crew member when

the DACS is either in Backup or Emergency mode of operation. The ERU50 is a bulkhead mounted unit.

The ERU50 is powered from the corresponding cabin Audio Control Panel (ACP) power output which

comes from the AMU50 Audio Management Unit (AMU). The ERU50 is controlled either by the

corresponding cabin ACP NORM Mode output or by the corresponding AMU ACP power output.

The ERU STATUS DISCRETE functionality is intended for activating an alert on the AMU.

1.4 Specifications

1.4.1 Electrical Specifications

Power Supply

Input Current: 500 mA maximum @ 28.0 Vdc

Normal Operating Conditions:

Nominal: +28.0 Vdc

Maximum: +30.3 Vdc

Minimum: +22.0 Vdc

Emergency: +18.0 Vdc

Abnormal Operating Conditions:

Maximum: +32.2 Vdc

Minimum: +20.5 Vdc

ERU50-001 Emergency Relay Unit

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Input Signals

Microphone Inputs

Quantity: 2

Circuit Type: Differential, passive feed through

Rated Level: 30 Vrms maximum

Maximum Current: 1A maximum

Headphones Inputs

Quantity: 2

Circuit Type: Differential, passive feed through

Rated Level: 30 Vrms maximum

Maximum Current: 1A maximum

Transmit Key Inputs

Quantity: 2

Maximum Current: 1A maximum

Intercommunication System Key Inputs

Quantity: 2

Maximum Current: 1A maximum

ERU Status Discrete Selection

Quantity: 1

Maximum Current: 1A maximum

AMU ACP 3 Power

Quantity: 1

Rated Input Level: 30 Vdc maximum

Maximum Current: 1A maximum

ACP 3 NORM Mode

Quantity: 1

Rated Level: Active low, <15 mA

Input Protection: Diode protected to +28 Vdc maximum

Output Signals

Microphone Outputs

Quantity: 2

Circuit Type: Differential, passive feed through

Rated Level: 30 Vrms maximum

Maximum Current: 1A maximum

Headphones Outputs

Quantity: 2

Circuit Type: Differential, passive feed through

Rated Level: 30 Vrms maximum

Maximum Current: 1A maximum

Transmit Key Outputs

Quantity: 2

Maximum Current: 1A maximum

ERU50-001 Emergency Relay Unit

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Intercommunication System Key Outputs

Quantity: 2

Maximum Current: 1A maximum

ACP Power Output

Quantity: 1

Rated Level: 30 Vdc maximum

Maximum Current: 1A maximum

ERU Status

Quantity: 1

Maximum Current: 1A maximum

1.4.2 Physical Specifications

Height 1.30 in (33.0 mm) maximum

Depth 2.65 in (67.3 mm) maximum

Width 4.54 in (115.3 mm) maximum

Weight 0.32 lbs (0.15 kg.) maximum

Mounting Bulkhead Mount: Four 10-32 screws

Material and Finish Metal components are brushed aluminum with

conversion coating.

Connectors One 37 pin D-Sub Male Jack post locking hardware

Bonding ≤2.5 mΩ resistance when installed in accordance with

the manufacturer’s instructions

Installation Kit ERU50-IKC

1.4.3 Environmental Specifications

Temperature -40 to +70°C (ambient)

-55 to +85°C (survival)

Altitude 50,000 feet max

Humidity 95% Non-condensing

Shock Operational shock; 6 g for 11 ms

Crash safety (impulse); 20 g for 11 ms

Crash safety (sustained); 20 g for 3 s

Section 1 ends

ERU50-001 Emergency Relay Unit

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Section 2 Installation

2.1 Introduction

Information in this section consists of unpacking and inspection procedures, installation procedures,

post-installation checks and installation drawings for the ERU50-001 Emergency Relay Unit

Review all notes, warnings and cautions.

2.2 Unpacking and Inspection

Unpack the equipment carefully and locate the warranty card. Inspect the unit visually for damage due to

shipping and report all such claims immediately to the carrier involved. Check that all items listed below

are present before proceeding and report any shortage immediately to your supplier:

- Warranty Card

- Certificate of Conformity or Release Certification

2.2.1 Warranty

All Cobham products are warranted for 2 years from date of installation by an authorized Cobham dealer,

to be free of defects in workmanship or performance. This warranty covers all materials and labour, but is

exclusive of any transport to deliver the defective unit to and from Cobham or its designated warranty

repair center, or any labour to remove or re-install the defective unit in the aircraft. Contact Cobham for

any questions regarding this warranty, its applicability to your units and/or for return authorization.

Cobham is the final arbitrator concerning warranty administration. Units which have been physically

damaged, burned, immersed in water or otherwise abused beyond the scope of normal use will not be

considered for warranty.

2.3 Airworthiness Limitations

The Airworthiness Limitations section is FAA approved and specifies inspections and other maintenance

required under 14 CFR §§ 43.16 and 91.403, unless an alternative program has been FAA approved.

Maintenance of the ERU50 is “on condition” only. Periodic maintenance of this product is not required.

2.4 Installation Procedures

Installation Notice

This product must be installed in accordance with the installation instructions provided in the latest issue

of this Installation and Operation Manual. All risk associated with installation of this product contrary to

these instructions shall be the responsibility of the installing agency.

ERU50-001 Emergency Relay Unit

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2.4.1 Warnings

N/A

2.4.2 Cautions

N/A

2.4.3 Cabling and Wiring

All wire shall be selected in accordance with the original aircraft manufacturer's Maintenance Instructions

or AC43.13-1B Change 1, Paragraphs 11-76 through 11-78. Unshielded wire types shall qualify to

MIL-W-22759 as specified in AC43.13-1B Change 1, Paragraphs 11-85, 11-86, and listed in Table 11-11.

For shielded wire applications, use Tefzel MIL-C-27500 shielded wire with solder sleeves (for shield

terminations) to make the most compact and easily terminated interconnect. Follow the connector map in

Section 2.6 as required.

Allow 3" from the end of the shielded wiring to the shield termination to allow the connector hood to be

easily installed. Reference the interconnect drawing in Section 2.6 for shield termination details. Note that

the hood is a "clamshell" hood, and is installed after the wiring is complete.

Maintain wire segregation and route wiring in accordance with the original aircraft manufacturers

Maintenance Instructions.

Unless otherwise noted, all wiring shall be a minimum of 22 AWG. Refer to the Interconnect drawing for

additional specifications. Check that the ground connection is clean and well secured, and that it shares

no path with any electrically noisy aircraft accessories such as blowers, turn and bank instruments or

similar loads.

2.4.4 Post-Installation Checks

2.4.4.1 Voltage/Resistance Checks

Do not attach the ERU50 until the following conditions are met.

Check the following:

a) Check P1001, pins <20> <21> and <34> for continuity to ground (less than 0.5Ω).

2.4.4.2 Power On Checks

Power up the aircraft’s systems and confirm normal operation of all functions with the ERU50-001

Emergency Relay Unit connected.

Upon satisfactory completion of all performance checks, make all required log book entries, electrical

load, weight and balance amendments and other documentation as required by your local regulatory

agency before releasing the aircraft for service.

ERU50-001 Emergency Relay Unit

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2.4.5 Functional Requirements

The functionality of the ERU50-001 is described in Table 1 below:

ACP1

ACP2

ACP3

ACP4

Functionality:

N N N N

USER 1 through USER 4 connected to their associated port on the

AMU

ERU Status is HI/OPEN

B/E X X X

USER 3 Mic, Phone, ICS Key and TX Key signals connected to USER 1

ACP3 is not powered

USER 4 Mic, Phone, ICS Key and TX Key signals connected to USER 2

ACP4 is not powered

ERU Status is LO/GROUND

X B/E X X

USER 3 Mic, Phone, ICS Key and TX Key signals connected to USER 1

ACP3 is not powered

USER 4 Mic, Phone, ICS Key and TX Key signals connected to USER 2

ACP4 is not powered

ERU Status is LO/GROUND

N N B/E N

USER 3 Mic, Phone, ICS Key and TX Key signals connected to USER 1

ACP3 is not powered

USER 2 and USER 4 connected to their associated port on the AMU

ERU Status is LO/GROUND

N N N B/E

USER 4 Mic, Phone, ICS Key and TX Key signals connected to USER 2

ACP4 is not powered

USER 1 and USER 3 connected to their associated port on the AMU

ERU Status is LO/GROUND

N N B/E B/E

USER 3 Mic, Phone, ICS Key and TX Key signals connected to USER 1

ACP3 is not powered

USER 4 Mic, Phone, ICS Key and TX Key signals connected to USER 2

ACP4 is not powered

ERU Status is LO/GROUND

Table 1 - ERU50-001 Functionality

Table Legend: N = Normal Mode

B/E = Backup or Emergency Mode

X = Mode irrelevant

ERU50-001 Emergency Relay Unit

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2.4.6 Minimum Performance Requirements

Refer to Section 2.4.5 Functional Requirements. Electrical continuity in both default and switched modes

is shown in the tables below:

AMU50 Connections

AMU USER 1 MIC

AMU USER 1 PHN

AMU USER 1 ICS KEY

AMU USER 1 TX KEY

AMU ACP3 POWER

AMU USER 3 MIC

AMU USER 3 PHN

AMU USER 3 ICS KEY

AMU USER 3 TX KEY

ERU STATUS IN

(To Alert)

ACP1

H/S1 MIC

H/S1 PHN

ACP1 ICS

ACP1 TX

ACP3

ACP3 POWER

H/S3 MIC

H/S3 PHN

ACP3 ICS

ACP3 TX

ERU STATUS OUT

(To Ground)

Table 2 - Default Mode

AMU50 Connections

AMU USER 1 MIC

AMU USER 1 PHN

AMU USER 1 ICS KEY

AMU USER 1 TX KEY

AMU ACP3 POWER

AMU USER 3 MIC

AMU USER 3 PHN

AMU USER 3 ICS KEY

AMU USER 3 TX KEY

ERU STATUS IN

(To Alert)

ACP1

H/S1 MIC

H/S1 PHN

ACP1 ICS

ACP1 TX

ACP3

ACP3 POWER

H/S3 MIC

H/S3 PHN

ACP3 ICS

ACP3 TX

ERU STATUS OUT

(To Ground)

Table 3 - Switched Mode

ERU50-001 Emergency Relay Unit

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2.4.7 Alert Configuration

When used as part of a Cobham Digital Audio Communications System (DACS), the ERU50 J1001 pin

25 (ERU STATUS OUT) is connected to AMU50 J103 pin 47 (ALERT 1). See Interconnect

ERU50\001\403-0 Note 6.

This alert must be configured through the Device Configuration Software (DevCs) to be Activation Low,

as shown below. For full information refer to the DevCs Installation and Operation manual.

DevCs Device Configuration Programmer window showing Alert 1.

2.5 Accessories Required But Not Supplied

Installation kit p/n ERU50-IKC (crimp) is required to complete the installation. The kit consists of the

following:

Quantity Description NAT Part No.

1 D-Sub, MIL Spec., 37 Socket, Crimp Housing 20-21-370

37 MS Crimp Socket 20-26-901

1 Hoods, D-Sub, Metal 20-28-037

1 Tag Ring, Shield Termination 20-30-416

2.6 Installation Drawings

DOCUMENT

REV.

DESCRIPTION

TYPE

SERIAL NO.

ERU50\001\403-0 1.00 Emergency Relay Unit Interconnect (2 sheets) All

ERU50\001\405-0 1.00 Emergency Relay Unit Connector Map All

ERU50\001\922-0 1.01 Emergency Relay Unit Mechanical Installation All

Section 2 ends following the above documents

Alert 1 configured to Active Low

ERU50-001 Emergency Relay Unit

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Installation and Operation Manual Issue 1.01 Page 3-1

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Section 3 Operation

3.1 Introduction

Information in this section consists of functional and operational procedures for the ERU50-001

Emergency Relay Unit.

3.2 General Information

The ERU50 is an Emergency Relay Unit for use with the Cobham Digital Audio Communication System

(DACS).

The ERU50-001 Emergency Relay Unit has no operator accessible controls. During installation, it may be

determined that internal level adjustments are required. Qualified personnel only shall complete internal

level adjustments.

Section 3 ends

COBHAM ERU50-001 Operating instructions

COBHAM ERU50-001 Operating instructions

COBHAM ERU50-001 Operating instructions

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